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arXiv 2303.08072hep-ph
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π子气体中粲介子分子的热能

Thermal Energy of a Charm-meson Molecule in a Pion Gas

Eric Braaten, Li-Ping He, Kevin Ingles, Jun Jiang

AI总结:

本文利用零程有效场论计算了π子气体中松散束缚粲介子分子传播子的次领头阶热修正,发现该修正仅微小降低其结合能并引起极小的热宽度变化,有利于在重离子碰撞中观测X(3872)和T_cc^+(3875)。

摘要:

使用零程有效场论,在重介子展开的次领头阶计算了π子气体中松散束缚的粲介子分子传播子的热修正。粲介子对自能中的紫外发散被粲介子对接触顶点的修正所抵消。在粲介子对阈值处奇异的项可以被吸收为粲介子组分的静止能量和动力学质量的热修正。剩余的项简化为对束缚动量的热修正,该修正与π子数密度成正比,并受π子/粲介子质量比的抑制。该修正导致π子气体中粲介子分子相对于粲介子对阈值的结合能出现微小降低,并且其热宽度的变化与粲介子组分的热宽度相比很小。这些结果对于在重离子碰撞产生的膨胀强子气体中观测 $X(3872)$ 和 $T_{cc}^+(3875)$ 的前景是令人鼓舞的。

英文摘要:

The thermal corrections to the propagator of a loosely bound charm-meson molecule in a pion gas are calculated to next-to-leading order in the heavy-meson expansion using a zero-range effective field theory. Ultraviolet divergences in the charm-meson-pair self energy are canceled by corrections to the charm-meson-pair contact vertex. Terms that are singular at the charm-meson-pair threshold can be absorbed into thermal corrections to the rest energies and kinetic masses of the charm-meson constituents. The remaining terms reduce to a thermal correction to the binding momentum that is proportional to the pion number density and suppressed by the pion/charm-meson mass ratio. The correction gives a tiny decrease in the binding energy of the charm-meson molecule relative to the charm-meson-pair threshold in the pion gas and a change in its thermal width that is small compared to the thermal widths of the charm-meson constituents. These results are encouraging for the prospects of observing $X(3872)$ and $T_{cc}^+(3875)$ in the expanding hadron gas produced by heavy-ion collisions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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